1. Field of the Invention
the present invention relates to a copy prevention apparatus and a method of preventing intellectual property such as computer software or semiconductor circuits form being copied illegally.
2. Description of the Prior Art
In software on the market for personal computers, a special countermeasure against illegal copying has been conventionally provided for the memory medium. For example, copy program operation is disabled by inhibiting part of memory medium from being read by ordinary methods. Furthermore, even if software is copied without copying the inhibited part of the memory medium, when the inhibited part can be read normally at the start of software or when the erroneous phenomenon caused when the inhibited part is not read, is different from that determined by the original software, the program is stopped because the software itself determines that the program has been copied illegally.
Furthermore, in the case of semiconductor circuits such as microprocessors, unnecessary gates disabled by ion implantation have been conventionally provided by copy prevention, so that when the gates are copied, the circuit will not operate normally.
In the prior-art software copy prevention method, however, even if some countermeasure has been considered for the memory medium, since violators who copy software, compare the illegally copied software with the original, and improves the copying means by repeatedly analyzing the difference between the two until the copied software can operate normally, it has been difficult to prevent software from being illegally copied in this manner.
On the other hand, in the case of software, since the value of software cannot be recognized until the software is actually used, when the software is protected perfectly, there exists a problem in that the user must purchase software for which value is unknown at the risk of disuse.
Furthermore, in the case of semiconductor circuits, violators who want to copy the circuits can realize the circuits on bread boards as they are by repeatedly searching for the causes when the circuits do not operate normally.
As described above, in the prior-art software copy prevention method, new methods of removing the copy protection are always being sought and therefore a vicious and meaningless cycle of protection development and protection removal is repeated. On the other hand, there exists another problem in that the value of software is recognized only after the software has been tested. Therefore, there exists a strong need for providing a more perfect means for preventing intellectual property such as software or semiconductor circuits from being copied illegally.